Diagnostic and prognostic benefits of computed tomography coronary angiography using the 2016 National Institute for Health and Care Excellence guidance within a randomised trial

Coronary artery disease in atrial fibrillation ablation: impact on arrhythmic outcomes

AIMS

Catheter ablation (CA) is an established treatment for atrial fibrillation (AF). A computed tomography (CT) may be performed before ablation to evaluate the anatomy of pulmonary veins. The aim of this study is to investigate the prevalence of patients with coronary artery disease (CAD) detected by cardiac CT scan pre-ablation and to evaluate the impact of CAD and revascularization on outcomes after AF ablation.

METHODS AND RESULTS

All consecutive patients with AF diagnosis, hospitalized at Universitair Ziekenhuis Brussel, Belgium, between 2015 and 2019, were prospectively screened for enrolment in the study. Inclusion criteria were (i) AF diagnosis, (ii) first procedure of AF ablation with cryoballoon CA, and (iii) contrast CT scan performed pre-ablation. A total of 576 consecutive patients were prospectively included and analysed in this study. At CT scan, 122 patients (21.2%) were diagnosed with CAD, of whom 41 patients (7.1%) with critical CAD. At survival analysis, critical CAD at CT scan was a predictor of atrial tachyarrhythmia (AT) recurrence during the follow-up, only in Cox univariate analysis [hazard ratio (HR) = 1.79] but was not an independent predictor in Cox multivariate analysis. At Cox multivariate analysis, independent predictors of AT recurrence were as follows: persistent AF (HR = 2.93) and left atrium volume index (HR = 1.04).

CONCLUSION

In patients undergoing CT scan before AF ablation, critical CAD was diagnosed in 7.1% of patients. Coronary artery disease and revascularization were not independent predictors of recurrence; thus, in this patient population, AF ablation should not be denied and can be performed together with CAD treatment.

Comparison of two diagnostic strategies for patients with stable chest pain suggestive of chronic coronary syndrome: rationale and design of the double-blind, pragmatic, randomized and controlled OPERATE Trial

BACKGROUND

To achieve potential financial savings and avoid exposing the patients to unnecessary risk, an optimal diagnostic strategy to identify low risk individual who may derive minimal benefit from further cardiac imaging testing (CIT) is important for patients with stable chest pain (SCP) suggestive of chronic coronary syndrome (CCS). Although several diagnostic strategies have been recommended by the most recent guidelines, few randomized controlled trials (RCTs) have prospectively investigated the actual effect of applying these strategies in clinical practice.

METHODS

OPERATE (OPtimal Evaluation of stable chest pain to Reduce unnecessAry utilization of cardiac imaging TEsting) trial is an investigator-initiated, multicenter, coronary computed tomography angiography (CCTA)-based, 2-arm parallel-group, double-blind, pragmatic and confirmative RCT planning to include 800 subjects with SCP suggestive of CCS. After enrollment, all subjects will be randomized to two arms (2016 U.K. National Institute of Health and Care Excellence guideline-determined and 2019 European Society of Cardiology guideline-determined diagnostic strategy) on a 1:1 basis. According to each strategy, CCTA should be referred and deferred for a subject in high and low risk group, respectively. The primary (effectiveness) endpoint is CCTA without obstructive coronary artery disease. Safety of each strategy will be mainly assessed by 1-year major adverse cardiovascular event rates.

DISCUSSION

The OPERATE trial will provide comparative effectiveness and safety evidences for two different diagnostic strategies for patients with SCP suggestive of CCS, with the intension of improving the diagnostic yield of CCTA at no expense of safety.

CLINICAL TRIAL REGISTRATION

ClinicalTrial.org Identifier NCT05640752.

Diagnostic and Therapeutic Strategies for Stable Coronary Artery Disease Following the ISCHEMIA Trial

Until recently, coronary revascularization with coronary artery bypass grafting or percutaneous coronary intervention has been regarded as the standard choice for stable coronary artery disease (CAD), particularly for patients with a significant burden of ischemia. However, in conjunction with remarkable advances in adjunctive medical therapy and a deeper understanding of its long-term prognosis from recent large-scale clinical trials, including ISCHEMIA (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches), the approach to stable CAD has changed drastically. Although the updated evidence from recent randomized clinical trials will likely modify the recommendations for future clinical practice guidelines, there are still unresolved and unmet issues in Asia, where prevalence and practice patterns are markedly different from those in Western countries. Herein, the authors discuss perspectives on: 1) assessing the diagnostic probability of patients with stable CAD; 2) application of noninvasive imaging tests; 3) initiation and titration of medical therapy; and 4) evolution of revascularization procedures in the modern era.

[Contribution of coroscanner in chronic coronary syndrome]

Cardiac division imaging by coroscanner has progressed a lot in 20 years to gradually become an important and potentially indispensable tool of chronic coronary cardiology. The European and American recommendations are Grade I for the assessment of symptomatic patients at intermediate to high risk, at the same level as traditional functional tests. The development of sophisticated post-treatment algorithms that apply the equations of fluid mechanics makes it possible to calculate an FFR value at any point from the CT image of the coronary artery. This FFR-CT is correctly correlated with invasive FFR compared to a threshold value of 0.80 and helps guide therapeutic choices. Thus, the coroscanner is a complement or an alternative to traditional functional tests and is positioned as a filter of access to coronary angiography, especially since it combines, from the same examination, a precise anatomical description, and a functional evaluation of the various possible lesions. Which is the Holy Grail of coronary cardiology.

Comparison of Risk Assessment Strategies for Patients with Diabetes Mellitus and Stable Chest Pain: A Coronary Computed Tomography Angiography Study

BACKGROUND

To compare two risk assessment strategies to identify individuals likely to benefit from further imaging testing in patients with diabetes mellitus (DM) and stable chest pain (SCP) suspected of obstructive coronary artery disease (CAD).

METHODS

602 DM patients referred to coronary computed tomography angiography (CCTA) for SCP were included. They were divided into high- and low-risk groups according to the 2016 National Institute of Health and Care Excellence guideline-determined strategy (NICE strategy) which focused on symptom evaluation and 2019 European Society of Cardiology guideline-determined strategy (ESC strategy) which was based on pretest probability (PTP) sequentially determined by the ESC-PTP estimator and risk factor-weighted clinical likelihood (RF-CL) model, respectively. The associations of clinical outcomes with risk groups and net reclassification improvement (NRI) were evaluated.

RESULTS

The NICE and ESC strategy classified 44% and 39% patients into the low-risk group, respectively. Compared to the NICE strategy, the ESC strategy indicated stronger associations between risk groups and events (hazard ratios: 4.24 versus 1.91), intensive clinical management, and a positive NRI (27.71%, p < 0.0001). The application of the RF-CL model ameliorated the underestimation of risk in patients with borderline ESC-PTP, which principally account for the improvement of the ESC strategy.

CONCLUSION

Compared to the NICE strategy, the ESC strategy seemed to be associated with greater efficiency in identifying high risk individuals in patients with DM and SCP.

Comparison of Different Investigation Strategies to Defer Cardiac Testing in Patients With Stable Chest Pain

OBJECTIVES

This study aimed to compare the current 5 investigation strategies to defer cardiac testing in patients with stable chest pain.

BACKGROUND

For the clinical management of stable chest pain, the identification of patients unlikely to benefit from further cardiac testing is important, but the most appropriate investigation strategy is unknown.

METHODS

A total of 4,207 patients referred to coronary computed tomography angiography for stable chest pain were classified into low- and high-risk groups according to the 2016 National Institute of Health and Care Excellence (NICE) guideline-determined strategy; PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) minimal risk tool-based strategy; 2019 European Society of Cardiology (ESC) guideline-determined strategy; and coronary artery calcium score (CACS), either in isolation (the CACS strategy) or as part of a weighted clinical likelihood model-based strategy (the CACS-CL strategy). The associations of obstructive coronary artery disease on coronary computed tomography angiography, major adverse cardiovascular events, and subsequent clinical management with risk groups according to different strategies were evaluated and compared.

RESULTS

The NICE, PROMISE, ESC, CACS, and CACS-CL strategies classified a proportion (22.63%, 29.21%, 41.84%, 46.76%, and 51.41%, respectively) of patients into low-risk groups. Compared with the NICE, PROMISE, ESC, and CACS strategies, the CACS-CL strategy had a stronger association between risk groups and obstructive coronary artery disease (odd ratios: 16.00 vs 2.93, 5.53, 7.94, and 10.39, respectively), major adverse cardiovascular events (HRs: 6.83 vs 1.90, 2.94, 4.23, and 5.13, respectively) and intensive subsequent clinical management as well as better metrics of diagnostic accuracy and positive net reclassification improvement.

CONCLUSIONS

Among contemporary strategies used to identify patients with stable chest pain at low risk, the use of CACS, especially when combined with clinical risk features, showed the strongest potential to effectively defer cardiac testing.

TCT Connect 2020 Trial Update: FORECAST, COMBINE OCT-FFR and DEFINE-PCI

Recent studies reported at TCT Connect 2020 have investigated a number of open clinical questions regarding the role of coronary physiology and the assessment of plaque morphology for diagnosis (FORECAST), risk stratification (COMBINE OCT-FFR) and treatment evaluation (DEFINE-PCI) of patients with coronary artery disease. In this article, the authors provide a critical appraisal of these studies and evaluate how they add to the current evidence base for management of patients with epicardial coronary artery disease. Furthermore, they discuss their potential impact on clinical practice, limitations of these studies and unanswered clinical questions that are areas for future research.

Effect of radiographer-led intervention on reassurance, treatment satisfaction, and recurring chest pain in patients with a normal coronary computed tomography angiography-a randomized controlled trial

BACKGROUND

Chest pain is a common complaint in the general practitioner's (GP) office. Computed tomography (CT) is one of the main diagnostic tools available for assessing coronary artery disease (CAD), with a low probability of a false-negative result (<1%). Despite normal CT findings, many patients with non-coronary chest pain believe they suffer from CAD.

AIMS

To determine the effect of an intervention on reassurance, treatment satisfaction, and recurring chest pain in patients with non-coronary chest pain at follow-up after 1 month.

METHODS

Patients with chest pain, but with normal coronary CT angiography, i.e., no CAD, were randomized into two groups. The intervention group received extended information about the CT examination, including visualization of their individual coronary calcium score images, before the radiographer conveyed the final examination result. The control group received standard care, i.e., neither extended information nor the examination result and were encouraged to consult their referring cardiologist or GP after 1 week. Items from the Seattle Angina Questionnaire and a question regarding reassurance measured the effect of the intervention at follow-up after 1 month.

RESULTS

The study included 92 patients, 63 female and 29 male, with a follow-up response rate of 80%. Reassurance and overall treatment satisfaction were significantly higher in the intervention group (P = 0.016 and P = 0.046 respectively). The incidence of chest pain was significantly reduced in the intervention group (P = 0.042).

CONCLUSION

This study demonstrated that the intervention group showed significantly higher reassurance, overall treatment satisfaction, and experienced significantly less chest pain at follow-up after 1 month.

CLINICAL TRIALS DATABASE ID

NCT03781661.

Coronary computed tomography angiography in patients with stable coronary artery disease

The treatment of coronary artery disease (CAD), which is defined by stable anatomical atherosclerotic and functional alterations of epicardial vessels or microcirculation, focuses on managing intermittent angina symptoms and preventing major adverse cardiovascular events with optimal medical therapy. When patients with known CAD present with angina and no acute coronary syndrome, they have historically been evaluated with a variety of noninvasive stress tests that utilize electrocardiography, radionuclide scintigraphy, echocardiography, or magnetic resonance imaging for determining the presence and extent of inducible myocardial ischemia. Patient event-free survival, however, is largely driven by the coronary atherosclerotic disease burden, which is not directly assessed by functional testing. Direct evaluation of coronary atherosclerotic disease by coronary computed tomography angiography (coronary CTA) has emerged as the first line noninvasive imaging modality as it improves diagnostic accuracy and positively influences clinical management. Compared to functional assessment of CAD, coronary CTA-guided management results in improved patient outcomes by facilitating prevention of myocardial infarction. Other strengths of coronary CTA include detailed atherosclerotic plaque characterization and the ability to assess functional significance of specific lesions, which may further improve risk assessment and prognosis and lead to more appropriate referrals for additional testing, such as invasive coronary angiography.

Serum Dickkopf-3 Level Is Inversely Associated with Significant Coronary Stenosis in an Asymptomatic Chinese Cohort

Dickkopp-3 (DKK3) has been identified to play a protection role against atherosclerosis. However, little is known about the relationship between serum DKK3 levels and subclinical coronary atherosclerosis. We aimed to investigate the association of serum DKK3 with coronary stenosis in an asymptomatic Chinese population. A total of 550 Chinese adults aged 40-60 years and without symptoms or histories of cardiovascular diseases were randomly selected to undergo coronary computed tomography angiography. We defined ≥ 50% luminal narrowing as significant coronary stenosis and measured serum DKK3 levels by an enzyme-linked immunosorbent assay (ELISA). Fifty-nine participants had significant coronary stenosis and 223 had < 50% coronary stenosis. Proportions of significant coronary stenosis were 13.7%, 11.4%, and 7.1% in DKK3 tertiles 1-3, respectively (P_trend = 0.0427). In the univariable multinomial logistic regression model, a decreasing DKK3 tertile was associated with significant coronary stenosis with borderline significance (OR: 1.40; 95% confidence intervals (CI): 0.98-1.99, P = 0.0642). In the multivariable regression model, participants in the lowest DKK3 tertile were associated with a 1.42-fold increased risk of significant coronary stenosis than those in the highest DKK3 tertile (OR: 2.42; 95% CI: 1.10-5.33; P = 0.0279) after adjustment for conventional cardiovascular risk factors. In addition, associations between DKK3 and significant coronary stenosis were consistent among subgroups. However, no significant association was found between serum DKK3 levels and < 50% coronary stenosis. Therefore, we have added to the existing evidence that serum DKK3 is inversely associated with the risk of significant coronary stenosis in asymptomatic middle-aged Chinese.

Non-invasive imaging of the coronary arteries

Non-invasive imaging of the coronary arteries is an enterprise in rapid development. From the research perspective, there is great demand for in vivo techniques that can reliably identify features of high-risk plaque that may offer insight into pathophysiological processes and act as surrogate indicators of response to therapeutic intervention. Meanwhile, there is clear clinical need for greater accuracy in diagnosis and prognostic stratification. Fortunately, ongoing technological improvements and emerging data from randomized clinical trials are helping make these elusive goals a reality. This review provides an update on the current status of non-invasive coronary imaging with computed tomography, magnetic resonance, and positron emission tomography with a focus on current clinical applications and future research directions.

Non-obstructive high-risk plaques increase the risk of future culprit lesions comparable to obstructive plaques without high-risk features: the ICONIC study

AIMS

High-risk plaque (HRP) and non-obstructive coronary artery disease independently predict adverse events, but their importance to future culprit lesions has not been resolved. We sought to determine in patients prior to confirmed acute coronary syndrome (ACS) the association between lesion percent diameter stenosis (%DS), and the absolute number and prevalence of HRP. The secondary objective was to examine the relative importance of non-obstructive HRP in future culprit lesions.

METHODS AND RESULTS

Within the ICONIC study, a nested case-control study of patients undergoing coronary computed tomographic angiography (coronary CT), we included ACS cases with culprit lesions confirmed by invasive coronary angiography and coregistered to baseline coronary CT. Quantitative CT was used to evaluate obstructive (≥50%) and non-obstructive (<50%) diameter stenosis, with HRP defined as ≥2 features of spotty calcification, positive remodelling, or low-attenuation plaque at baseline. A total of 234 patients with downstream ACS over 54 (interquartile range 5-525.5) days exhibited 198/898 plaques with HRP on coronary CT. While HRP was less prevalent in non-obstructive (19.7%, 161/819) than obstructive lesions (46.8%, 37/79, P < 0.001), non-obstructive plaque comprised 81.3% (161/198) of HRP lesions overall. Among the 128 patients with identifiable culprit lesion precursors, the adjusted hazard ratio (HR) was 1.85 [95% confidence interval (CI) 1.26-2.72] for HRP, with no interaction between %DS and HRP (P = 0.82). Compared to non-obstructive HRP lesions, obstructive lesions without HRP exhibited a non-significant HR of 1.41 (95% CI 0.61-3.25, P = 0.42).

CONCLUSIONS

While HRP is more prevalent among obstructive lesions, non-obstructive HRP lesions outnumber those that are obstructive and confer risk clinically approaching that of obstructive lesions without HRP.

Imaging in the Evaluation of Chest Pain in the Primary Care Setting, Part 1: Cardiovascular Etiologies

Chest pain is a common presenting complaint in the primary care setting. Imaging plays a key role in the evaluation of the multiple organ systems that can be responsible for chest pain. With numerous imaging modalities available, determination of the most appropriate test and interpretation of the findings can be a challenge for the clinician. In this 2-part series, we offer resources to guide primary care physicians in the selection of imaging studies and present the imaging findings of various causes of nonemergent chest pain. In Part 1, we focus on a discussion of the basic concepts of each imaging technique and the appearance of common cardiovascular etiologies of chest pain.

Natural course of coronary artery calcium progression in Asian population with an initial score of zero

Background

We aimed to investigate the natural course of coronary artery calcium progression in an Asian population with a baseline coronary artery calcium (CAC) score of zero, and to determine subclinical coronary atherosclerosis.

Methods

Four hundred fifty-nine subjects with at least two CAC scans with an initial score of zero were included. CAC progression (+) was defined by the development of any CAC (i.e., CAC > 0) during subsequent CT scans. Clinical characteristics and Framingham risk profiles were also recorded.

Results

Among 459 subjects, 106 (23.09%) experienced CAC progression during the average follow-up period of 5.71 ± 2.68 years. Older age, male gender, HDL-C, total cholesterol and higher Framingham risk score were independently associated with CAC progression. Framingham risk score had the better discriminative ability (AUC = 0.660) to predict CAC progression compared to the other parameters with a sensitivity of 75.24% and specificity of 53.95%. For the double zero score with coronary artery atherosclerosis prediction, older age, triglycerides, hypertension, and Framingham risk score were significantly associated with these events. Among these parameters, Framingham risk score may be a relatively acceptable parameter with high negative predictive (NPV = 96.4%) value to rule out double zero score with obstructive coronary artery atherosclerosis scenario with an optimum cut-off value of <16.9 (AUC =0.652, sensitivity of 57.69%; specificity of 68.82%).

Conclusions

A baseline zero CAC score in asymptomatic Chinese population with low to intermediate risk have a low incidence for CAC progression within the 5-years period. For CAC progression prediction, Framingham risk score with the cutoff < 11.1 may help confirm subjects at low risk to improve cardiovascular risk stratification and reclassification in the field of preventive cardiology.

Clinical outcomes of patients discharged from the Rapid Access Chest Pain Clinic with non-anginal chest pain: A retrospective cohort study

BACKGROUND

The Rapid Access Chest Pain Clinic (RACPC) has become an important means of assessing patients who present with ischaemic or ischaemia-like symptoms of recent onset. Observations have shown that up to 70% are discharged with a diagnosis of non-anginal chest pain (NACP) and accordingly "reassured". This study aims to describe the actual clinical outcomes of this cohort of patients discharged from the RACPC.

METHODS

We undertook a single centre retrospective cohort study at a tertiary cardiac hospital. The outcomes of unselected patients diagnosed with NACP and discharged from the RACPC between April 2010 and March 2013 at University Hospitals of Leicester (UHL) were recorded. Re-referrals to cardiology outpatient clinic and emergency hospital admissions for cardiovascular disease within 6 months, and the mortality rate at 12 months, were determined.

RESULTS

7066 patients were seen in the UHL RACPC during the 36-month period. 3253 (46.0%) were diagnosed with NACP and discharged. 7 (0.2%) were diagnosed with coronary artery disease (CAD) and 8 (0.25%) cases of acute coronary syndrome (ACS) identified during the review period. 11 (0.3%) patients died within 12 months of discharge from RACPC. No deaths were attributable to CAD.

CONCLUSIONS

Comprehensive assessment using risk-stratification criteria in a nurse practitioner-led RACPC can accurately identify patients who are at low-risk for subsequent CAD. Despite contemporary National Institute for Health and Care Excellence (NICE) guidelines that shift focus away from a clinical judgement based approach, this strategy appears to robustly predict favourable outcomes in patients diagnosed with NACP.

Plasma Choline as a Diagnostic Biomarker in Slow Coronary Flow

Aim

The slow coronary flow (SCF) phenomenon was characterized by delayed perfusion of epicardial arteries, and no obvious coronary artery lesion in coronary angiography. The prognosis of patients with slow coronary flow was poor. However, there is lack of rapid, simple, and accurate method for SCF diagnosis. This study aimed to explore the utility of plasma choline as a diagnostic biomarker for SCF.

Methods

Patients with coronary artery stenosis <40% evaluated by the coronary angiogram method were recruited in this study and were grouped into normal coronary flow (NCF) and SCF by thrombolysis in myocardial infarction frame count (TFC). Plasma choline concentrations of patients with NCF and SCF were quantified by Ultra Performance Liquid Chromatography Tandem Mass Spectrometry. Correlation analysis was performed between plasma choline concentration and TFC. Receiver operating characteristic (ROC) curve analysis with or without confounding factor adjustment was applied to predict the diagnostic power of plasma choline in SCF.

Results

Forty-four patients with SCF and 21 patients with NCF were included in this study. TFC in LAD, LCX, and RCA and mean TFC were significantly higher in patients with SCF in comparison with patients with NCF (32.67 ± 8.37 vs. 20.66 ± 3.41, P  <  0.01). Plasma choline level was obviously higher in patients with SCF when compared with patients with NCF (754.65 ± 238.18 vs. 635.79 ± 108.25, P=0.007). Plasma choline level had significantly positive correlation with Mean TFC (r = 0.364, P=0.002). Receiver operating characteristic (ROC) analysis showed that choline with or without confounding factor adjustment had an AUC score of 0.65 and 0.77, respectively.

Conclusions

TFC were closely related with plasma choline level, and plasma choline can be a suitable and stable diagnostic biomarker for SCF.

Evaluation of Myocardial Ischemia Using Coronary Computed Tomography Angiography in Patients with Stable Angina

안정형 협심증 환자에서 관상동맥질환의 치료 여부를 결정하고 임상 결과를 예측하기 위해서는 심근허혈의 평가가 중요하다. 현재 심근허혈 진단의 표준검사법으로 분획혈류예비력 검사법이 인정되나 침습적 검사라는 제한점이 있다. 또한, 관상동맥 전산화단층촬영은 형태적인 관상동맥질환 진단에 유용한 방법으로 정립되었지만, 혈역학적으로 유의한 협착에 의한 심근허혈 진단에는 한계가 있다. 최근 이러한 문제를 해결하고자 관상동맥 전산화단층촬영 영상을 기반으로 측정한 관상동맥 죽상경화판의 정량화, 심근관류, 그리고 심근 분획혈류예비력을 이용한 연구들이 진행되어 왔고, 그 진단적 가치를 점차 인정받고 있다. 본 종설에서는 심근허혈진단과 관련된 관상동맥 전산화단층촬영 혈관조영술의 여러 영상기법들에 대해서 알아보고자 한다.

Guiding Therapy by Coronary CT Angiography Improves Outcomes in Patients With Stable Chest Pain

BACKGROUND

Within the SCOT-HEART (Scottish COmputed Tomography of the HEART Trial) trial of patients with stable chest pain, the use of coronary computed tomography angiography (CTA) reduced the rate of death from coronary heart disease or nonfatal myocardial infarction (primary endpoint).

OBJECTIVES

This study sought to assess the consistency and mechanisms of the 5-year reduction in this endpoint.

METHODS

In this open-label trial, 4,146 participants were randomized to standard care alone or standard care plus coronary CTA. This study explored the primary endpoint by symptoms, diagnosis, coronary revascularizations, and preventative therapies.

RESULTS

Event reductions were consistent across symptom and risk categories (p = NS for interactions). In patients who were not diagnosed with angina due to coronary heart disease, coronary CTA was associated with a lower primary endpoint incidence rate (0.23; 95% confidence interval [CI]: 0.13 to 0.35 vs. 0.59; 95% CI: 0.42 to 0.80 per 100 patient-years; p < 0.001). In those who had undergone coronary CTA, rates of coronary revascularization were higher in the first year (hazard ratio [HR]: 1.21; 95% CI: 1.01 to 1.46; p = 0.042) but lower beyond 1 year (HR: 0.59; 95% CI: 0.38 to 0.90; p = 0.015). Patients assigned to coronary CTA had higher rates of preventative therapies throughout follow-up (p < 0.001 for all), with rates highest in those with CT-defined coronary artery disease. Modeling studies demonstrated the plausibility of the observed effect size.

CONCLUSIONS

The beneficial effect of coronary CTA on outcomes is consistent across subgroups with plausible underlying mechanisms. Coronary CTA improves coronary heart disease outcomes by enabling better targeting of preventative treatments to those with coronary artery disease. (Scottish COmputed Tomography of the HEART Trial [SCOT-HEART]; NCT01149590).

[Radiological imaging to assess individual cardiovascular risk]

CLINICAL/METHODICAL ISSUE

Radiologic imaging for the assessment of individual cardiovascular risk.

STANDARD RADIOLOGICAL METHODS

The correct estimation of the individual cardiovascular risk is prerequisite for the prevention of cardiovascular diseases. Here, extensive evidence is available for coronary calcium scans as well as coronary CT angiography (CTA).

METHODICAL INNOVATIONS

Summary of the available evidence for the use of calcium score and coronary CTA. Illustration of the significance of both tests in current guidelines.

PERFORMANCE

Both tests have high prognostic value, surpassing a risk-factor based assessment. In comparison with the calcium score, the CTA has higher incremental value.

ACHIEVEMENTS

Results from recent trials confirm an improvement of outcomes in symptomatic patients by performing a CTA compared with standard care.

PRACTICAL RECOMMENDATIONS

European and US guidelines recommend a calcium score for risk stratification of asymptomatic patients with a low to intermediate risk profile. For symptomatic patients with low to intermediate coronary artery disease pretest probability, a CTA is recommended.

A zero coronary artery calcium score in patients with stable chest pain is associated with a good prognosis, despite risk of non-calcified plaques

Objectives

To estimate the prevalence of non-calcified coronary artery disease (CAD) in patients with suspected stable angina and a zero coronary artery calcification (CAC) score, and to assess the prognostic significance of a zero CAC in these symptomatic patients.

Methods

In this prospective cohort study, consecutive patients with stable chest pain underwent CAC scoring ± CT coronary angiography (CTCA) as part of routine clinical care at a single tertiary centre over 7 years. Major adverse cardiac event (MACE) was defined as cardiac death, non-fatal myocardial infarction and/or non-elective revascularisation.

Results

A total of 915 of 1753 (52.2%) patients (mean age 56.8 ± 12.0 years; 46.2% male) had a zero CAC score. Of the 751 (82.1%) patients with a zero CAC in whom CTCA was performed, 674 (89.7%) had normal coronary arteries, 63 (8.4%) had non-calcified CAD with < 50% stenosis and 14 (1.9%) had ≥ 50% stenosis in at least one coronary artery. The negative predictive value of a zero CAC for excluding a ≥ 50% CTCA stenosis was 98.1%. Over a median follow-up period of 2.2 years (range 1.0-7.0 years), the absolute annualised rates of MACE were as follows: zero CAC 1.9 per 1000 person-years and non-zero CAC 7.4 per 1000 person-years (HR 3.8, p = 0.009). However, after adjusting for age, gender and cardiovascular risk factors using a multivariable Cox proportional hazards model, there was no statistically significant difference in the risk of MACE between the two patient cohorts (p = 0.19). After adjusting for age, gender and cardiovascular risk factors, the HR for all-cause mortality among the zero CAC cohort vers non-zero CAC was 2.1 (p = 0.27).

Conclusion

A zero CAC score in patients undergoing CT scanning for suspected stable angina has a high negative predictive value for the exclusion of obstructive CAD and is associated with a good medium-term prognosis.

The rationale for the primacy of coronary CT angiography in the National Institute for Health and Care Excellence (NICE) guideline (CG95) for the investigation of chest pain of recent onset

The National Institute for Health and Care Excellence (NICE) provides independent evidence-based guidance for England's National Health Service. Its 2010 guideline for the "assessment and diagnosis of recent onset chest pain or discomfort of suspected cardiac origin" (CG95) recommended a variety of first-line investigations in stable patients, depending on the pre-test probability (PTP) of obstructive coronary artery disease (CAD). Following a limited review, NICE produced an updated version of CG95 in 2016. Formal calculation of PTP is no longer advised. Coronary computed tomographic angiography (CCTA) is recommended as the first-line investigation for all patients with angina (or non-anginal pain but an abnormal electrocardiogram) and no prior CAD, with second-line functional imaging if the CCTA is equivocal. Notwithstanding some controversies regarding NICE's methodology, the updated version of CG95 can be justified on several levels. The focus on angina reflects evidence that patients with non-anginal pain have a similar prevalence of CAD to an asymptomatic population, and may not benefit from further investigation. The elimination of PTP is reasonable in patients required to have cardiac-sounding (anginal) symptoms. The ability of CCTA to identify non-obstructive atheroma, invisible to functional testing, might lead to improved medical treatment. Conversely the argument sometimes made for first-line functional testing, that ischemia-guided coronary revascularization leads to improved outcomes, has little hard evidence to support it. The performance of a separate functional test following equivocal CCTA may improve diagnostic specificity, and similar information is now obtainable from the CT study itself via computational flow dynamics.

Coronary CT Angiography and 5-Year Risk of Myocardial Infarction

BACKGROUND

Although coronary computed tomographic angiography (CTA) improves diagnostic certainty in the assessment of patients with stable chest pain, its effect on 5-year clinical outcomes is unknown.

METHODS

In an open-label, multicenter, parallel-group trial, we randomly assigned 4146 patients with stable chest pain who had been referred to a cardiology clinic for evaluation to standard care plus CTA (2073 patients) or to standard care alone (2073 patients). Investigations, treatments, and clinical outcomes were assessed over 3 to 7 years of follow-up. The primary end point was death from coronary heart disease or nonfatal myocardial infarction at 5 years.

RESULTS

The median duration of follow-up was 4.8 years, which yielded 20,254 patient-years of follow-up. The 5-year rate of the primary end point was lower in the CTA group than in the standard-care group (2.3% [48 patients] vs. 3.9% [81 patients]; hazard ratio, 0.59; 95% confidence interval [CI], 0.41 to 0.84; P=0.004). Although the rates of invasive coronary angiography and coronary revascularization were higher in the CTA group than in the standard-care group in the first few months of follow-up, overall rates were similar at 5 years: invasive coronary angiography was performed in 491 patients in the CTA group and in 502 patients in the standard-care group (hazard ratio, 1.00; 95% CI, 0.88 to 1.13), and coronary revascularization was performed in 279 patients in the CTA group and in 267 in the standard-care group (hazard ratio, 1.07; 95% CI, 0.91 to 1.27). However, more preventive therapies were initiated in patients in the CTA group (odds ratio, 1.40; 95% CI, 1.19 to 1.65), as were more antianginal therapies (odds ratio, 1.27; 95% CI, 1.05 to 1.54). There were no significant between-group differences in the rates of cardiovascular or noncardiovascular deaths or deaths from any cause.

CONCLUSIONS

In this trial, the use of CTA in addition to standard care in patients with stable chest pain resulted in a significantly lower rate of death from coronary heart disease or nonfatal myocardial infarction at 5 years than standard care alone, without resulting in a significantly higher rate of coronary angiography or coronary revascularization. (Funded by the Scottish Government Chief Scientist Office and others; SCOT-HEART ClinicalTrials.gov number, NCT01149590 .).

Comparison of International Guidelines for Assessment of Suspected Stable Angina: Insights From the PROMISE and SCOT-HEART

OBJECTIVES

This study sought to compare the performance of major guidelines for the assessment of stable chest pain including risk-based (American College of Cardiology/American Heart Association and European Society of Cardiology) and symptom-focused (National Institute for Health and Care Excellence) strategies.

BACKGROUND

Although noninvasive testing is not recommended in low-risk individuals with stable chest pain, guidelines recommend differing approaches to defining low-risk patients.

METHODS

Patient-level data were obtained from the PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) and SCOT-HEART (Scottish Computed Tomography of the Heart) trials. Pre-test probability was determined and patients dichotomized into low-risk and intermediate-high-risk groups according to each guideline's definitions. The primary endpoint was obstructive coronary artery disease on coronary computed tomography angiography. Secondary endpoints were coronary revascularization at 90 days and cardiovascular death or nonfatal myocardial infarction up to 3 years.

RESULTS

In total, 13,773 patients were included of whom 6,160 had coronary computed tomography angiography. The proportions of patients identified as low risk by the American College of Cardiology/American Heart Association, European Society of Cardiology, and National Institute for Health and Care Excellence guidelines, respectively, were 2.5%, 2.5%, and 10.0% within PROMISE, and 14.0%, 19.8%, and 38.4% within SCOT-HEART. All guidelines identified lower rates of obstructive coronary artery disease in low- versus intermediate-high-risk patients with a negative predictive value of ≥0.90. Compared with low-risk groups, all intermediate-high-risk groups had greater risks of coronary revascularization (odds ratio [OR]: 2.2 to 24.1) and clinical outcomes (OR: 1.84 to 5.8).

CONCLUSIONS

Compared with risk-based guidelines, symptom-focused assessment identifies a larger group of low-risk chest pain patients potentially deriving limited benefit from noninvasive testing. (Scottish Computed Tomography of the Heart Trial [SCOT-HEART]; NCT01149590; Prospective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550).

Prospective Comparison of FFR Derived From Coronary CT Angiography With SPECT Perfusion Imaging in Stable Coronary Artery Disease: The ReASSESS Study

OBJECTIVES

This study sought to compare the per-patient diagnostic performance of coronary computed tomography angiography (CTA)-derived fractional flow reserve (FFR_CT) with that of single-photon emission computed tomography (SPECT), using a fractional flow reserve (FFR) value of ≤0.80 as the reference for diagnosing at least 1 hemodynamically significant stenosis in a head-to-head comparison of patients with intermediate coronary stenosis as determined by coronary CTA.

BACKGROUND

No previous study has prospectively compared the diagnostic performance of FFR_CT and myocardial perfusion imaging by SPECT in symptomatic patients with intermediate range coronary artery disease (CAD).

METHODS

This study was conducted at a single-center as a prospective study in patients with stable angina pectoris (N = 143). FFR_CT and SPECT analyses were performed by core laboratories and were blinded for the personnel responsible for downstream patient management. FFR_CT ≤0.80 distally in at least 1 coronary artery with a diameter ≥2 mm classified patients as having ischemia. Ischemia by SPECT was encountered if a reversible perfusion defect (summed difference score ≥2) or transitory ischemic dilation of the left ventricle (ratio >1.19) were found.

RESULTS

The per-patient diagnostic performance for identifying ischemia (95% confidence interval [CI]), FFR_CT versus SPECT, were sensitivity of 91% (95% CI: 81% to 97%) versus 41% (95% CI: 29% to 55%; p < 0.001); specificity of 55% (95% CI: 44% to 66%) versus 86% (95% CI: 77% to 93%; p < 0.001); negative predictive value of 90% (95% CI: 82% to 98%) versus 68% (95% CI: 59% to 77%; p = 0.001); positive predictive value of 58% (95% CI: 48% to 68%) versus 67% (95% CI: 51% to 82%; p = NS); and accuracy of 70% (95% CI: 62% to 77%) versus 68% (95% CI: 60% to 75%; p = NS) respectively.

CONCLUSIONS

In patients with stable chest pain and CAD as determined by coronary CTA, the overall diagnostic accuracy levels of FFR_CT and SPECT were identical in assessing hemodynamically significant stenosis. However, FFR_CT demonstrated a significantly higher diagnostic sensitivity than SPECT.

Validity of inducible ischaemia as a surrogate for adverse outcomes in stable coronary artery disease

Regional myocardial ischaemia is commonly expressed as exertional angina in patients with stable coronary artery disease (CAD). It also associates with prognosis, risk tending to increase with the severity of ischaemia. The validity of myocardial ischaemia as a surrogate for adverse clinical outcomes, however, has not been well established. Thus, in cohort studies, ischaemia testing has failed to influence rates of myocardial infarction and coronary death. Moreover, in clinical studies, pharmacological and interventional treatments that are effective in correcting ischaemia have rarely been shown to reduce cardiovascular (CV) risk. This contrasts with statins and other anti-inflammatory drugs that have no direct effect on ischaemia but improve CV outcomes by modifying the atherothrombotic disease process. Despite this, and with little evidence of patient benefit, stress testing is commonly used during the follow-up of patients with stable CAD when the demonstration of ischaemic change may be seen as a target for treatment, independently of symptomatic status. Substitution of a symptom-driven management strategy has the potential to reduce rates of non-invasive stress testing, unnecessary downstream revascularisation procedures and use of valuable resources in patients with stable CAD without adverse consequences for CV risk.

Identification of patients with stable chest pain deriving minimal value from coronary computed tomography angiography: An external validation of the PROMISE minimal-risk tool

BACKGROUND

The PROspective Multicenter Imaging Study for Evaluation of chest pain (PROMISE) minimal-risk tool was recently developed to identify patients with suspected stable angina at very low risk of coronary artery disease (CAD) and clinical events. We assessed the external validity of this tool within the context of the Scottish Computed Tomography of the HEART (SCOT-HEART) multicenter randomised controlled trial of patients with suspected stable angina due to coronary disease.

METHODS

The minimal-risk tool was applied to 1764 patients with complete imaging and follow-up data. External validity was compared with the guideline-endorsed CAD Consortium (CADC) risk score and determined through tests of model discrimination and calibration.

RESULTS

A total of 531 (30.1%, mean age 52.4years, female 62.0%) patients were classified as minimal-risk. Compared to the remainder of the validation cohort, this group had lower estimated pre-test probability of coronary disease according to the CADC model (30.0% vs 47.0%, p<0.001). The PROMISE minimal-risk tool improved discrimination compared with the CADC model (c-statistic 0.785 vs 0.730, p<0.001) and was improved further following re-estimation of covariate coefficients (c-statistic 0.805, p<0.001). Model calibration was initially poor (χ2 197.6, Hosmer-Lemeshow [HL] p<0.001), with significant overestimation of probability of minimal risk, but improved significantly following revision of the PROMISE minimal-risk intercept and covariate coefficients (χ2 5.6, HL p=0.692).

CONCLUSION AND RELEVANCE

Despite overestimating the probability of minimal-risk, the PROMISE minimal-risk tool outperforms the CADC model with regards to prognostic discrimination in patients with suspected stable angina, and may assist clinicians in decisions regarding non-invasive testing.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01149590.